SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3c1a6103044cad63dcd469d7f38291d894fe0d2feb7444fcc432ccb07db5a69' 
  AND token = 'MWHDKlQh/+2nbblQ5WjmWoTqnx5uKIzi/JcU1G4BVNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}